PSDR - SDR Radio Receiver Module: AM / FM / SSB / CW / DRM

Software-defined radio, or SDR
short (Software Defined Radio) is a radio communication system in
which the usual hardware components (such as mixers, filters,
amplifiers, modulators / demodulators, detectors, etc.) created
by PC software or firmware embedded in system. This is not a
game-changing technology.

Fig. 1: PSDR - SDR Receiver Module

The first mention can be found at
the end of the seventies, when Walter Tuttlebee described the
concept of VLF radio, utilizing A/D converter and microprocessor
Intel 8085th Furthermore followed SpeakeEasy project, focusing on
the U.S. defense system. His aim was to use digital signal
processing, and range from 2 to 2,000 MHz replace up to ten
existing military radios. The historical sequence we must not
forget also, the year 1991 when Joseph MITOL created and a year
later published extensive work on the subject, designed for a
wide field of technology. More information on the historical
development of SDR receivers can be found on the Internet.

Fig. 2: Block diagram of an analog receiver

Fig. 2b: Block diagram of the digital SDR receiver

Today the situation is much better
than it was in the early days of his birth. Since the SDR
receiver typically consists of several functional units
separately, it is possible to create a variety of different
approaches. From the highest when the input filter placed in one
or more of fast A / D converter, followed by a configurable gate
array (FPGA), taking care of the basic signal processing to the
simpler designed especially amateur construction. They are used
to digitize the signal usually Line-In input of your sound card
(see block diagram in Figure 3). Sampling frequency is equal to
the received range yet. Ie. when you use a sound card with a
sampling frequency such as 192 kHz is also available software
tunable range of 192 kHz. Greater extent then provides for the
exchange of crystals in the receiver or tunable oscillator (VCO).

Fig. 3: Block diagram of the SDR receiver, utilizing PC sound
card

PSDR Module
PSDR is easy to use SDR receiver module "Software Defined
Radio", for connection to a PC sound card. It is based
transistor crystal oscillator (crystals for 80 meters and 160
meters inside Gaza), Johnson counter with 7474 circuit group and
Tayloe detector circuits 4053rd After treatment, there are four
signals shifted by 0, 90, 180 and 270 degrees, which pass through
the low-pass band filtrate and the operational amplifier (typ.
NE5532) of them after amplification signals generated I / Q.

´
Fig. 4: PSDR - TOP

Fig. 5: PSDR - BOTTOM

Signals I / Q also lead to a
stereo line-in audio card and another decoding and listening to
old software. The advantage is that this is a diagram useful in a
very wide frequency range and the possible addition of switchable
input bandpass filters with their properties rivaling
professional, the amateur radio receivers.

Fig. 6: Schematic Diagram module PSDR

Unlike similar solutions, however,
are modules PSDR supplemented with external input generator and
the switch. Instead crystal oscillator can use any tunable
generator, like this: PGEN45 - Generator 8 kHz to 45 MHz

Application
Using SDR receiver is very versatile and is based on a wide
frequency range. Virtually can be used to receive all services in
long, medium and short waves AM, NFM, WFM, LSB, USB, DSB, CW and
CW-L-U modulation. In addition to radio stations can also receive
amateur radio broadcasts, synoptic maps, military installations,
submarines, navigation beacons, and much more.

Example of use (frequency
in kHz):

150-281: Long Waves

520 - 1620: Medium waves

2300-21 of 850: Short waves

3855, 4609, 7880, 8040:
Weather HF-Fax

4625: UVB-76 Russian military
base

9950, 9575, 6577, 5448:
Numbers station

4583: RTTY Teltype

And many, many others

Fig. 7: Location of components PSDR-1
TOP

Fig. 8: Location of components PSDR-1
TOP

Installing the receiver
PSDR modules are supported by all standard SDR software. Among
the most common are: WINSDR, HDSDR or a new open source SDR# (SDR
Sharp). Since this is a very interesting project, which is for
non-commercial use completely free of charge, we describe the use
PSDR module together with SDR#.

Fig. 9: Connectors on the module PSDR-1

Application does not need to
install, just download and unzip the following address:

After unpacking the software SDR#
ready to use! It is not necessary to install anything!

Fig. 10: The sdrsharp after unpacking

The first use PSDR module
After unpacking SDR# files can immediately start the application
SDRSharp.exe that after reading the following window:

Fig. 11: SDR sharp after its launch

For starters, you can try such as
receiver for receiving the classic AM radio broadcast:

1) First, connect the antenna to
the module, power supply (12V DC) and 3.5 jack to connect the
Line-In input of the sound card
2) Enter the desired crystal or potentiometer to adjust the VCO
frequency
3) Next, run the application SDRSharp.exe
4) Set the recording from line-in (no microphone)
5) In addition to the Play button to select "Other (Sound
Card)"
6) Select the type of modulation
7) Click the play button
5) Section Frequency set the receiving frequency
6) If everything works as it should, it should show the received
spectrum from PC speaker should hear noise or music

Fig. 12: SDR sharp and reception of radio stations
(RTL SDR)

Of course SDR# is not the only
application that supports modules PSDR. Among the most common is
that, inter alia also WINSDR or HDSDR
and many others.